A variety of medical procedure tools have been proposed that are introduced into a body cavity by insertion through the instrument channel of an endoscope and used to carry out specific procedures such as ligation, suturing, or sampling of biological tissues. One example of this type of medical procedure tool is a conventionally known medical ligation unit such as disclosed in Japanese Unexamined Patent Application, First Publication No. 2003-204966 (paragraphs 0020-0040, FIGS. 1 to 5). This medical ligation unit enables the process of ligating a lesion site inside a body cavity using a ligating wire, and cutting the tightened ligating wire to be carried out as a series of operations.
This medical ligation unit is equipped with a medical ligation tool which is retained inside the body, and an operating device for guiding the medical ligation tool into the body and then performing the ligating operation. The medical ligation tool is provided with the aforementioned ligating wire, which has a folded over portion at its base end side, and a receiving member, which is for holding the ligating wire at the front of the folded over portion in a manner to permit free advance and retraction. The receiving member has an annular projection located at roughly the center along its axial direction, and is for exposing the ligating wire to the outside, while at the same time serving as the contact surface for the cutting blade, explained below.
The operating device has an inner sheath that comes into contact with the base end side of the receiving member. A finger ring is connected to the base end side of the inner sheath via the main body of the operator. The receiving member engages with the front end of the inner sheath. A slider that is freely advancing and retracting with respect to the operator main body is attached to the operator main body. An operating wire, which is inserted through the inner sheath and has an engaging member at its front end, is connected to this slider. This engaging member is designed to engage with the folded over portion of the ligating wire. In other words, by fixing the operator main body in place and then advancing or retracting the slider, the diameter of the ligating wire can be increased or decreased.
A cutting sheath is provided to the periphery of the inner sheath, and covers this inner sheath in a freely advancing and retracting manner. A cutting operator is connected to the base end side of the cutting sheath. This cutting operator is disposed to the front end side of the operator main body, and comes into contact with the operator main body so that it cannot move in the base end direction. An annular cutting blade is formed at the front end of the cutting sheath.
When ligating a lesion site inside a body cavity using a medical ligation unit designed as described above, the medical ligation unit is first attached to the procedure device. Namely, the receiving member is supported by the inner sheath as a result of catching the folded over portion of the ligating wire on the engaging member of the operating wire, engaging the receiving member in the front end of the inner sheath, and then the moving the slider in the base end direction. This arrangement unit is then introduced into the body cavity via an endoscope device or the like, and the ligating wire is then slipped around the lesion site. In this arrangement, the operator main body is fixed in place, the slider is moved toward the base end direction, and the diameter of the ligating wire is reduced. As a result, the lesion site is tied off, cutting off blood flow to the site. Once tied off, with the operator main body fixed in place, the cutting operator is pushed in the forward direction. Namely, the cutting sheath is moved in the forward direction along the inner sheath.
As a result, the cutting blade formed at the front end of the cutting sheath is moved toward the annular projection on the receiving member, and the ligating wire that is externally exposed at this annular projection is cut. After cutting the ligating wire, the cutting blade comes into contact with the contact surface of the annular projection. As a result, the ligating wired tying off the lesion site is cut away and the ligating procedure is completed. When the ligating wire is cut, the receiving member falls out from the inner sheath and drops into the body, where it is subsequently naturally eliminated.
The present invention was conceived in view of the above-described circumstances, and has as its objective the provision of a medical procedure tool for cutting a linear material such as ligating wire or the like with certainty after performing a specific procedure to a biological tissue, while at the same time not requiring overly troublesome procedures following cutting.